HADOOP集群安装（官方文档翻译）

Cluster Setup：集群安装

Purpose

Prerequisites

Installation

Configuration

Configuration Files

Site Configuration

Configuring the Environment of the Hadoop Daemons

Configuring the Hadoop Daemons

Memory monitoring

Slaves

Logging

Cluster Restartability

MapReduce

Hadoop Rack Awareness

Hadoop Startup

Hadoop Shutdown

Purpose：目的

This document describes how to install, configure and manage non-trivial Hadoop clusters ranging from a few nodes to extremely large clusters with thousands of nodes.

这个文档描述怎样安装，配置和管理non-trivial（不知如何翻译）HADOOP集群，从很少节点到数以千计的大量节点。

To play with Hadoop, you may first want to install Hadoop on a single machine (see Single Node Setup).

执行HADOOP，你可以先安装HADOOP到单个机器上。

Prerequisites：需要

Make sure all required software is installed on all nodes in your cluster.

Download the Hadoop software.

确保需要的软件被安装到集群的所有节点机器上

下载HADOOP软件

Installation：安装

Installing a Hadoop cluster typically involves unpacking the software on all the machines in the cluster.

安装HADOOP集群通常包括在集群所有机器上解压软件。

Typically one machine in the cluster is designated as the NameNode and another machine the as JobTracker,
exclusively. These are the masters. The rest of the machines in the cluster act as both DataNode and TaskTracker.
These are theslaves.

通常集群中的一台机器被指定为NameNode，其他的机器作为JobTracker，特别的，这些机器是主用机器，集群中剩下的机器作为数据节点和TaskTracker，他们是从节点。

The root of the distribution is referred to as HADOOP_HOME. All machines in the cluster usually have the same HADOOP_HOMEpath.

根目录称为HADOOP_HOME，集群中所有的机器通常拥有相同的HADOOP_HOME路径。